Astronauts sleep in 'pods that look like padded broom closets'

Astronauts Pam Melroy, George Zamka, and European Space Agency's Paolo Nespoli, sleep in their sleeping bags, which are secured on the middeck of the Space Shuttle Discovery while docked with the International Space Station.
AP Photo/NASA
After months of intense training and a white-knuckled trip through the ozone layer at nine times the speed of a rifle bullet, you can bet that NASA astronauts need to bank some rest.

Space sailors log really long hours throughout their days on tasks that require intense concentration, which is why NASA schedules precisely 8.5 hours of sleep per 24 on deck.

How exactly does 'nighttime' play out in space?

The International Space Station (ISS) orbits the Earth at 17,150 miles per hour, clocking one lap around our planet every hour and a half. Doing the math, this means 16 sunsets every 24 hours — a new day every 90 minutes.

Fascinating, yes, but this unrelenting motion can create colossal jet lag and wreak havoc on an astronaut's internal body clock.

What time zone do they use?

I'm guessing no cushy mattresses?

The crew members are provided sleep pods that look like padded broom closets. They have custom sleeping sacks fastened to a wall or the ceiling, lest they float about the cabin.

According to retired astronaut Marsha Ivins, who spent 42 days in space on five different missions, their sleeping bag has armholes that allow you to reach outside the bag to zip it up. You then settle yourself in by tightening the attached Velcro straps. If you don't tuck your appendages into the bag, they'll drift out in front of you.

Canadian astronaut Chris Hadfield offers this video tour of his very own sleep sack aboard the ISS. After showing off his astro-PJs you can watch him zip up and close the doors to his pod.

Pillows?

That's a whole other issue. Though not everyone wants or needs one, Ivins says she did, to help her neck relax. She actually attached her head to a block of foam.

"You put the back of your head on [the 'pillow']," she says, "and then you Velcro the front of your head to it."

What about parasomnias? Any chance of sleepwalking?

Reuters/Ho New
Actually there was one reported case of … drifting.

According to a British reporter, one Russian crew member apparently preferred to do without a sleep pod or sleeping bag. His fellow crewmembers, still awake after he turned in, saw him float by — presumably in the midst of sweet dreams. They watched him "bouncing off the walls, his course set by the air currents that gently pushed and pulled him."

Do they end up getting their hard eight?

No. As hard as they try to get comfy, most astronauts don't get enough rest. Many are routinely sleep deficient, logging just six hours of sleep every 24 hours.

However, some astronauts speculate that these short sleep sessions may be the result of the body's feeling less fatigued in a microgravity environment. Less fatigue may equal less sleep need.

Do they report any weird dreams?

According to dream studies conducted aboard the Russian space shuttle Mir, astronauts experience significantly diminished REM sleep in space compared to us Earthlings. They are therefore continually monitored for any and all ill effects.

"Efforts are planned to understand more fully the spaceflight environment and the role that other factors may play in reducing or promoting sleep," said Lauren Leveton, PhD, senior research scientist in NASA's Behavioral Health and Performance Division.

Who wakes them up when it's 'morning'?

During the 30-year space shuttle program, which ended in 2011, it was a NASA tradition to have wake-up calls during the shuttle missions. Each "morning" at the scheduled wake-up time, ground operations broadcast a song into the space shuttle cabin. A wide range of musical styles were played, including rock, pop, western and classical.

Each song was selected for a particular astronaut. Sometimes the astronauts requested the tune; other times their families selected a song with special meaning.

Unfortunately, the wake-up service is not available on the ISS. There, the crew must use a regular alarm clock.